diff --git a/xos/configurations/common/mydeployment.yaml b/xos/configurations/common/mydeployment.yaml
index ab7d3c2..a0fd8ed 100644
--- a/xos/configurations/common/mydeployment.yaml
+++ b/xos/configurations/common/mydeployment.yaml
@@ -7,10 +7,27 @@
 
 topology_template:
   node_templates:
+    m1.large:
+      type: tosca.nodes.flavor
+
+    m1.medium:
+      type: tosca.nodes.flavor
+
+    m1.small:
+      type: tosca.nodes.flavor
+
     MyDeployment:
       type: tosca.nodes.Deployment
-      properties:
-          flavors: m1.large, m1.medium, m1.small
+      requirements:
+          m1.large:
+             node: m1.large
+             relationship: tosca.relationships.SupportsFlavor
+          m1.medium:
+             node: m1.medium
+             relationship: tosca.relationships.SupportsFlavor
+          m1.small:
+             node: m1.small
+             relationship: tosca.relationships.SupportsFlavor
 
     mysite:
       type: tosca.nodes.Site
diff --git a/xos/tosca/custom_types/xos.m4 b/xos/tosca/custom_types/xos.m4
index 9bd504a..c114652 100644
--- a/xos/tosca/custom_types/xos.m4
+++ b/xos/tosca/custom_types/xos.m4
@@ -748,13 +748,6 @@
                 type: string
                 required: false
                 description: default isolation to use when bringing up instances (default to 'vm')
-            default_flavor:
-                # Note: we should probably formally introduce flavors to Tosca
-                # at some point, and use a requirement/relationship instead of
-                # a text string.
-                type: string
-                required: false
-                description: default flavor to use for slice
             network:
                 type: string
                 required: false
@@ -785,6 +778,20 @@
             node:
                 type: tosca.capabilities.xos.NodeLabel
 
+    tosca.nodes.Flavor:
+        derived_from: tosca.nodes.Root
+        description: >
+            An XOS Flavor.
+        properties:
+            xos_base_props
+            flavor:
+                type: string
+                required: false
+                description: openstack flavor name
+        capabilities:
+            flavor:
+                type: tosca.capabilities.xos.Flavor
+
     tosca.nodes.DashboardView:
         derived_from: tosca.nodes.Root
         description: >
@@ -923,6 +930,14 @@
         derived_from: tosca.relationships.Root
         valid_target_types: [ tosca.capabilities.xos.NodeLabel ]
 
+    tosca.relationships.SupportsFlavor:
+        derived_from: tosca.relationships.Root
+        valid_target_types: [ tosca.capabilities.xos.Flavor ]
+
+    tosca.relationships.DefaultFlavor:
+        derived_from: tosca.relationships.Root
+        valid_target_types: [ tosca.capabilities.xos.Flavor ]
+
     tosca.relationships.ProvidesAddresses:
         derived_from: tosca.relationships.Root
         valid_target_types: [ tosca.capabilities.xos.AddressPool ]
@@ -978,6 +993,10 @@
         derived_from: tosca.capabilities.Root
         description: An XOS NodeLabel
 
+    tosca.capabilities.xos.Flavor:
+        derived_from: tosca.capabilities.Root
+        description: An XOS Flavor
+
     tosca.capabilities.xos.Image:
         derived_from: tosca.capabilities.Root
         description: An XOS Image
diff --git a/xos/tosca/custom_types/xos.yaml b/xos/tosca/custom_types/xos.yaml
index f790cc5..a89641c 100644
--- a/xos/tosca/custom_types/xos.yaml
+++ b/xos/tosca/custom_types/xos.yaml
@@ -1159,13 +1159,6 @@
                 type: string
                 required: false
                 description: default isolation to use when bringing up instances (default to 'vm')
-            default_flavor:
-                # Note: we should probably formally introduce flavors to Tosca
-                # at some point, and use a requirement/relationship instead of
-                # a text string.
-                type: string
-                required: false
-                description: default flavor to use for slice
             network:
                 type: string
                 required: false
@@ -1218,6 +1211,31 @@
             node:
                 type: tosca.capabilities.xos.NodeLabel
 
+    tosca.nodes.Flavor:
+        derived_from: tosca.nodes.Root
+        description: >
+            An XOS Flavor.
+        properties:
+            no-delete:
+                type: boolean
+                default: false
+                description: Do not allow Tosca to delete this object
+            no-create:
+                type: boolean
+                default: false
+                description: Do not allow Tosca to create this object
+            no-update:
+                type: boolean
+                default: false
+                description: Do not allow Tosca to update this object
+            flavor:
+                type: string
+                required: false
+                description: openstack flavor name
+        capabilities:
+            flavor:
+                type: tosca.capabilities.xos.Flavor
+
     tosca.nodes.DashboardView:
         derived_from: tosca.nodes.Root
         description: >
@@ -1367,6 +1385,14 @@
         derived_from: tosca.relationships.Root
         valid_target_types: [ tosca.capabilities.xos.NodeLabel ]
 
+    tosca.relationships.SupportsFlavor:
+        derived_from: tosca.relationships.Root
+        valid_target_types: [ tosca.capabilities.xos.Flavor ]
+
+    tosca.relationships.DefaultFlavor:
+        derived_from: tosca.relationships.Root
+        valid_target_types: [ tosca.capabilities.xos.Flavor ]
+
     tosca.relationships.ProvidesAddresses:
         derived_from: tosca.relationships.Root
         valid_target_types: [ tosca.capabilities.xos.AddressPool ]
@@ -1422,6 +1448,10 @@
         derived_from: tosca.capabilities.Root
         description: An XOS NodeLabel
 
+    tosca.capabilities.xos.Flavor:
+        derived_from: tosca.capabilities.Root
+        description: An XOS Flavor
+
     tosca.capabilities.xos.Image:
         derived_from: tosca.capabilities.Root
         description: An XOS Image
diff --git a/xos/tosca/resources/deployment.py b/xos/tosca/resources/deployment.py
index ed6734c..e5ab4b1 100644
--- a/xos/tosca/resources/deployment.py
+++ b/xos/tosca/resources/deployment.py
@@ -31,9 +31,8 @@
                 imageDep = ImageDeployments(deployment=obj, image=image)
                 imageDep.save()
 
-        # Be a little more lightweight with 'flavors'. Since we install flavors
-        # as a fixture rather than using TOSCA, we can just let the user
-        # use a comma-separated list.
+        # DEPRECATED - should switch to using a requirement, so tosca can do
+        # the topsort properly
 
         flavors = self.get_property("flavors")
         if flavors:
@@ -47,6 +46,15 @@
                     flavor.deployments.add(obj)
                     flavor.save()
 
+        # The new, right way
+        for flavor in self.get_requirements("tosca.relationships.SupportsFlavor"):
+            flavor = self.get_xos_object(Flavor, name=flavor)
+            if not flavor.deployments.filter(id=obj.id).exists():
+                self.info("Attached flavor %s to deployment %s" % (flavor, obj))
+                flavor.deployments.add(obj)
+                flavor.save()
+
+
         rolemap = ( ("tosca.relationships.AdminPrivilege", "admin"), )
         self.postprocess_privileges(DeploymentRole, DeploymentPrivilege, rolemap, obj, "deployment")
 
diff --git a/xos/tosca/resources/flavor.py b/xos/tosca/resources/flavor.py
new file mode 100644
index 0000000..f61ccad
--- /dev/null
+++ b/xos/tosca/resources/flavor.py
@@ -0,0 +1,37 @@
+# note: this module named xossite.py instead of site.py due to conflict with
+#    /usr/lib/python2.7/site.py
+
+import os
+import pdb
+import sys
+import tempfile
+sys.path.append("/opt/tosca")
+from translator.toscalib.tosca_template import ToscaTemplate
+
+from core.models import User, Deployment, Flavor
+
+from xosresource import XOSResource
+
+class XOSFlavor(XOSResource):
+    provides = "tosca.nodes.Flavor"
+    xos_model = Flavor
+    copyin_props = ["flavor"]
+
+    def get_xos_args(self):
+        args = super(XOSFlavor, self).get_xos_args()
+
+        # Support the default where the OpenStack flavor is the same as the
+        # flavor name
+        if "flavor" not in args:
+            args["flavor"] = args["name"]
+
+        return args
+
+    def delete(self, obj):
+        if obj.instance_set.exists():
+            self.info("Flavor %s has active instances; skipping delete" % obj.name)
+            return
+        super(XOSFlavor, self).delete(obj)
+
+
+
diff --git a/xos/tosca/resources/slice.py b/xos/tosca/resources/slice.py
index 48e5eb0..22978a2 100644
--- a/xos/tosca/resources/slice.py
+++ b/xos/tosca/resources/slice.py
@@ -31,7 +31,7 @@
             default_image = self.get_xos_object(Image, name=default_image_name, throw_exception=True)
             args["default_image"] = default_image
 
-        default_flavor_name = self.get_property_default("default_flavor", None)
+        default_flavor_name = self.get_requirement("tosca.relationships.DefaultFlavor", throw_exception=False)
         if default_flavor_name:
             default_flavor = self.get_xos_object(Flavor, name=default_flavor_name, throw_exception=True)
             args["default_flavor"] = default_flavor